Nonequilibrium materials composed of self-driven constituents – active
matter – presents novel physics to understand and may
one day provide new technologies such as autonomously moving and
self-healing materials
[1]}, [2]}, [3]}, [4]}, [5]}. One
central example is mixtures of cytoskeletal filaments and molecular
motors, which are important for their ability to form self-assembled
cellular structures such as the mitotic spindle and cell
cortex. Reduced in vitro systems show that biofilament and motor-protein mixtures can form self-organized patterns, such as vortices
and asters, reminiscent of cellular structures
[6]}, [7]}, [8]}. Recently, Sanchez et al.
[9]} synthesized mixtures of microtubules (MTs),
multimeric kinesin-1 motor complexes, ATP, and a depletant. In bulk,
extended MT bundles spontaneously form which continuously stretch,
bend and fracture, leading to large-scale flows. When condensed onto
an oil-water interface, the MTs form a nematically-ordered active
surface characterized by turbulent-like motions and motile
disclination defects.
